Hexanic Extracts of Trametes versicolor (L.:Fr.) Pilát to Control of Tomato Powdery Mildew

摘要

The powdery mildew on tomato (Leveillula taurica ) is one of the most important disease of this crop in Mexico, causing losses of up to 40% in yield. There are no resistant tomato cultivars, so their control is based on the use of chemical fungicides, mainly triazoles. With the objective of obtaining new alternatives to control of this desease, concentrations of 5, 7.5 and 10% (v/v) of Hexanic extracts of Trametes versicolor developed on Luffa aegyptiaca were evaluated comparing their effectiveness (Abbott) with Amistar Gold? (0.5 L·Ha~(-1)), Serenade Max? (5.0 kg·Ha~(-1)) and Control. 3 applications were made every 7 days and the experimental design used was randomized complete blocks with 4 replicates. The percentage of damaged leaf area was evaluated with an Exprofeso scale with 0 to 6 indices 7 days after the first and second application and at 7, 14 and 21 days after the third. The results obtained indicate that T. versicolor Hexanic extracts offers a control of L. taurica , with average control efficiencies of 47.41 and 57.82% and maximum of 58.16 and 65.09% for concentrations of 7.5 and 10% respectively, suggesting reduce the application interval from 7 to 5 days. The 5% concentration offered little significant control. L. aegyptiaca is considered to be an excellent substrate for the development and obtaining of mycelium of T. versicolor (R~(2): 0.9867). After applications of Hexanic extracts concentrations, phytotoxicity symptoms were not detected on the tomato crop cv Cid.